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United States Patent |
6,255,257
|
Yamada
,   et al.
|
July 3, 2001
|
Silicone grease composition
Abstract
A silicone grease composition having high thermal conductivity, comprising
(A) 50 to 95 weight % of a mixture of an aluminum nitride powder .alpha.
having an average particle size of 0.5 to 5 .mu.m and an aluminum nitride
powder .beta. having an average particle size of 6 to 20 .mu.m, wherein
the aluminum nitride powders .alpha. and .beta. are mixed so that the
.alpha./(.alpha.+.beta.) ratio by weight is from 0.1 to 0.9 and the
average particle size after mixing is from 1 to 10 .mu.m, (B) 5 to 15
weight % of organopolysiloxanes having a viscosity of from 50 to 50,000 cs
at 25.degree. C. and represented by formula R.sup.1.sub.a SiO.sub.(4-a)/2,
wherein R.sup.1 represents at least one group selected from saturated or
unsaturated univalent hydrocarbon groups containing 1 to 18 carbon atoms
and 1.8.ltoreq.a.ltoreq.2.2, and (C) 0 to 35 weight % of at least one
inorganic compound powder having an average particle size of 0.5 to 100
.mu.m selected from the group consisting of zinc oxide, alumina, boron
nitride and silicon carbide powders.
Inventors:
|
Yamada; Kunihiro (Gunma-ken, JP);
Takahashi; Takayuki (Gunma-ken, JP);
Isobe; Kenichi (Gunma-ken, JP)
|
Assignee:
|
Shin-Etsu Chemical Co., Ltd. (Tokyo, JP)
|
Appl. No.:
|
453469 |
Filed:
|
December 2, 1999 |
Foreign Application Priority Data
| Dec 02, 1998[JP] | 10-343037 |
Current U.S. Class: |
508/172; 508/155; 508/161; 508/208 |
Intern'l Class: |
C10M 107/50; C10M 113/08 |
Field of Search: |
508/172,208
|
References Cited
U.S. Patent Documents
4265775 | May., 1981 | Aakalu et al. | 252/573.
|
5100568 | Mar., 1992 | Takahashi et al. | 252/28.
|
5227081 | Jul., 1993 | Sawa et al. | 252/28.
|
5981641 | Nov., 1999 | Takahashi et al. | 524/428.
|
6015777 | Jan., 2000 | Lostritto, Jr. et al. | 508/208.
|
6114429 | Sep., 2000 | Yamada et al. | 524/423.
|
Primary Examiner: McAvoy; Ellen M.
Attorney, Agent or Firm: Millen White Zelano & Branigan
Claims
What is claimed is:
1. A silicone grease composition comprising:
(A) 50 to 95 weight % of a mixture of an aluminum nitride powder .alpha.
having an average particle size of 0.5 to 5 .mu.m and an aluminum nitride
powder .beta. having an average particle size of 6 to 20 .mu.m, wherein
the aluminum nitride powders .alpha. and .beta. are mixed so that the
.alpha./(.alpha.+.beta.) ratio by weight is from 0.1 to 0.9 and the
average particle size after mixing is from 1 to 10 .mu.m,
(B) 5 to 15 weight % of organopolysiloxanes having a viscosity of from 50
to 50,000 cs at 25.degree. C. and represented by formula R.sup.1.sub.a
SiO.sub.(4-a)/2 , wherein R.sup.1 represents at least one group selected
from saturated or unsaturated univalent hydrocarbon groups containing 1 to
18 carbon atoms and 1.8.ltoreq.a.ltoreq.2.2, and
(C) 0 to 35 weight % of at least one inorganic compound powder having an
average particle size of 0.5 to 100 .mu.m selected from the group
consisting of zinc oxide, alumina, boron nitride and silicon carbide
powders.
2. A silicone grease composition according to claim 1, wherein said mixture
of aluminum nitride powders .alpha. and .beta. has a specific surface area
of from 0.1 to 20 m.sup.2 /g.
3. A silicone grease composition according to claim 1, wherein the
saturated hydrocarbon groups are methyl groups and alkyl groups having 6
to 14 carbon atoms and the unsaturated hydrocarbon groups are phenyl
groups.
4. A silicone grease composition according to claim 1, wherein each of the
aluminum nitride powders .alpha. and .beta. has the surface rendered
hydrophobic by treatment with an organosilane, an organopolysiloxane or a
fluorine-containing organic compound.
5. The silicone grease composition according to claim 1, wherein the
aluminum nitride powder .alpha. has an average particle size of 1 to 3
.mu.m.
6. The silicone grease composition according to claim 1, wherein the
aluminum nitride powder .beta. has an average particle size of 7 to 15
.mu.m.
7. The silicone grease composition according to claim 1, average particle
size of the .alpha. and .beta. aluminum nitride powders, after mixing, is
from 2 to 5 .mu.m.
8. The silicone grease composition according to claim 1, wherein the
.alpha./(.alpha.+.beta.) ratio by weight is from 0.3 to 0.7.
9. The silicone grease composition according to claim 1, wherein the weight
% of said component (A) is from 60 to 90.
10. The silicone grease composition according to claim 2, wherein said
specific surface area is from 1 to 10 m.sup.2 /g.
11. The silicone grease composition according to claim 10, wherein said
specific surface area is from 2-5 m.sup.2 /g.
12. The silicone grease composition according to claim 1, wherein 1.9
.ltoreq.a.ltoreq.2.1.
13. The silicone grease composition according to claim 1, wherein said
organopolysiloxanes have a viscosity of 100 to 10,000 cs at 25 .degree. C.
14. The silicone grease composition according to claim 1, wherein the
weight % of said component (B) is 7 to 13.
15. The silicone grease composition according to claim 1, wherein the
weight % of said component (C) is at most 30.
16. The silicone grease composition according to claim 1, wherein the
weight % of said component (C) is 0 to 25.
17. The silicone grease composition of claim 1, which contains at least
some of compound (C).
Description
FIELD OF THE INVENTION
The present invention relates to a silicone grease composition having
excellent thermal conductivity.
BACKGROUND OF THE INVENTION
Most of electronic parts generate heat during the operation, and so the
heat removal therefrom is required for making them function properly. As
to heat-reducing materials applicable to electronic parts, there are high
expectations for aluminum nitride because of its high thermal conductivity
and electric insulation. The aluminum nitride can be used in various
forms, e.g., as a molding and a powder for the filler of grease or rubber.
For achieving high thermal conductivity by the use of aluminum nitride
powder as the filler of grease or rubber, it is necessary to raise the
filling rate of the aluminum nitride powder. In the case of grease,
therefore, the use of a wetter or the art of using as a base oil a
modified oil having good wettability has so far been proposed as a
solution for raising the filling rate. However, both proposals have failed
in achieving satisfactorily high filling rate of aluminum nitride to
result in being unsuccessful at obtaining high thermal conductivity.
SUMMARY OF THE INVENTION
As a result of our intensive study of the problem of raising thermal
conductivity by increasing the filling rate of aluminum nitride in
silicone grease, it has been found that a very good result can be obtained
when the filler used is a mixture of two kinds of aluminum nitride powders
differing in average particle size, thereby achieving the present
invention.
Therefore, an object of the invention is to provide a silicone grease
composition having especially high thermal conductivity.
The aforementioned object of the invention is attained with a silicone
grease composition comprising the following components (A) to (C):
(A) 50 to 95 weight % of a mixture of an aluminum nitride powder .alpha.
having an average particle size of 0.5 to 5 .mu.m and an aluminum nitride
powder .beta. having an average particle size of 6 to 20 .mu.m, wherein
the aluminum nitride powders .alpha. and .beta. are mixed so that the
.alpha./(.alpha.+.beta.) ratio is from 0.1 to 0.9 by weight and the
average particle size after mixing is from 1 to 10 .mu.m,
(B) 5 to 15 weight % of organopolysiloxanes having a viscosity of from 50
to 50,000 cs at 25.degree. C. and represented by formula R.sup.1.sub.a
SiO.sub.(4-a)/2, wherein R.sup.1 represents at least one group selected
from saturated or unsaturated univalent hydrocarbon groups containing 1 to
18 carbon atoms and 1.8.ltoreq.a.ltoreq.2.2, and
(C) 0 to 35 weight % of at least one inorganic compound powder having an
average particle size of 0.5 to 100 .mu.m selected from the group
consisting of zinc oxide, alumina, boron nitride and silicon carbide
powders.
DETAILED DESCRIPTION OF THE INVENTION
The aluminum nitride as the present Component (A) is obtained by mixing two
kinds of aluminum nitride powders, namely aluminum nitride powders .alpha.
and .beta. differing in average particle size. The grease composition can
have an increased filling rate by the combined use of the foregoing
fillers, compared with an individual use of either filler; as a result,
the thermal conductivity of the grease can be improved. The thermal
conductivity value the grease composition can acquire by the combined use
of the foregoing fillers is higher than that by the use of each of the
fillers in the greatest possible filling amount. Further, the consistency
the composition can have in the former case is higher (in other words, the
composition can be more softened) than that in the latter case, so that
the present composition has the advantage of handling easily.
The aluminum nitride powder a as one constituent of Component (A) is
required to have an average particle size in the range of 0.5 to 5 .mu.m.
This is because the filling rate of the thermal conductive silicone grease
composition cannot be raised so far as the average particle size of
aluminum nitride powder .alpha. is smaller than 0.5 .mu.m or greater than
5 .mu.m. In particular, it is desirable that the average particle size of
the aluminum nitride powder .alpha. be from 1 to 3 .mu.m. In analogy with
the aluminum nitride powder .alpha., the aluminum nitride powder .beta. as
the other constituent of Component (A) cannot contribute to raising the
filling rate of a thermal conductive silicone grease composition so far as
it has an average particle size smaller than 6 .mu.m or greater than 20
.mu.m. Therefore, the average particle size of aluminum nitride powder
.beta. is required to be from 6 to 20 .mu.m. In particular, it is
desirable that the aluminum nitride powder .beta. have an average particle
size in the range of 7 to 15 .mu.m.
In mixing the aluminum nitride powders .alpha. and .beta., the ratio
.alpha./(.alpha.+.beta.) is required to be in the range of 0.1 to 0.9 by
weight, because the filling rate in the resulting thermal conductive
silicone grease composition cannot be increased when the ratio
.alpha./(.alpha.+.beta.) is smaller than 0.1 or greater than 0.9 by
weight. In particular, it is desirable for the ratio
.alpha./(.alpha.+.beta.) to be from 0.3 to 0.7 by weight. Moreover, the
aluminum nitride powders thus mixed is required to have an average
particle size of from 1 to 10 .mu.m, because no homogeneous grease
composition can be obtained so far as the average particle size is smaller
than 1 .mu.m or greater than 10 .mu.m. When the average particle size is
from 2 to 5 .mu.m, better results can be obtained.
The total proportion of aluminum nitride powders .alpha. and .beta. in the
silicone grease composition is required to be from 50 to 95 weight %. This
is because the grease composition obtained cannot have satisfactory
thermal conductivity when the total proportion is lower than 50 weight %,
while it becomes hard and poor in speadability when the total proportion
is higher than 95 weight %. The preferred range of the total proportion is
from 60 to 90 weight %.
The powders of aluminum nitride usable in the invention are those of
nitride constituted of Group III and Group V elements and generally having
a hexagonal or wurtzite-type crystal structure and a white or grayish
white appearance. The particle shape thereof is amorphous or spherical
depending on the preparation method adopted.
The aluminum nitride powder usable as a raw material can be prepared, e.g.,
by a direct nitriding method wherein metallic aluminum powder is reacted
directly with nitrogen or ammonia, an alumina reducing method wherein a
mixed powder of alumina and carbon is heated in an atmosphere of nitrogen
or ammonia to effect the reduction and the nitriding at the same time, a
method of reacting an aluminum vapor directly with nitrogen, or a method
of thermally decomposing AlCl.sub.3.cndot.NH.sub.3.
In order to obtain aluminum nitride powders having the intended particle
sizes, the coarse powder prepared using the method as recited above is
ground with a vibration mill or a jet mill. In this step, the aluminum
nitride powders .alpha. and .beta. used in the invention can be obtained
by properly choosing the grinding time. Further, airflow classification
may be carried out after grinding step.
When the aluminum nitride powders .alpha. and .beta. have their individual
specific surface areas in the range of 0.1 to 20.sup.2 /g, they will serve
the purpose of preparing a homogeneous grease composition. And it is
desirable for the mixture of the aluminum nitride powders .alpha. and
.beta. to have its specific surface area in the range of 0.1-20 m.sup.2
/g, preferably 1-10 m.sup.2 /g, particularly preferably 2-5 m.sup.2 /g.
These values of the specific surface area are those determined according
to JIS K1150.
Although the characteristics of aluminum nitride powders, including the
chemical composition (impurities), the particle shape and the particle
size distribution, depend on the methods employed for preparing them, the
present aluminum nitride powders may be prepared by any of the preparation
methods as mentioned above, and they each may be a mixture of powders
prepared by different methods.
In addition, if desired, the surface of the present aluminum nitride
powders may be rendered hydrophobic by undergoing treatment with
organosilanes, organopolysiloxanes or fluorine-containing organic
compounds.
The treatment for imparting hydrophobicity to the aluminum nitride powder
surface may be carried out in a conventional way. For instance, the
aluminum nitride powders and an organosilane or partial hydrolysis
products thereof are mixed by means of a mixing machine, such as TRIMIX,
TWINMIX or PLANETARY MIXER (trade names, made by INOUE MFG., INC.), ULTRA
MIXER (trade name, made by MIZUHO INDUSTRIAL CO., LTD.) or HIVISDISPERMIX
(trade name, made by TOKUSHU KIKA KOGYO CO., LTD.). Therein, the mixing
system may be heated to a temperature of 50-150.degree. C., if desired.
Therein, they may be mixed in the presence of a solvent, such as toluene,
xylene, petroleum ether, mineral spirit, isoparaffin, isopropyl alcohol or
ethanol. After mixing, however, it is desirable that the solvent be
removed with, e.g., a vacuum apparatus.
On the other hand, it is possible to use as a diluting solvent a liquid
organopolysiloxane as Component (B) of the present composition. In this
case, the organopolysiloxane or its partial hydrolysis products used as
the treatment agent is mixed previously with the organopolysiloxane used
as Component (B), and thereto aluminum nitride powders are added. Thereby,
the treatment and the mixing can be carried out at the same time. The
composition prepared in such a manner is also included in the scope of the
invention.
In the formula R.sup.1.sub.a SiO.sub.(4-a)/2 representing
organopolysiloxanes used as Component (B) , R.sup.1 is at least one group
selected from saturated or unsaturated univalent hydrocarbon groups
containing 1 to 18 carbon atoms. Examples of such a hydrocarbon group
include an alkyl group, such as methyl, ethyl, propyl, hexyl, octyl,
decyl, dodecyl, tetradecyl or octadecyl; a cycloalkyl group, such as
cyclopentyl or cyclohexyl; an alkenyl group, such as vinyl or allyl; an
aryl group, such as phenyl or tollyl; an aralkyl group, such as
2-phenylethyl or 2-methyl-2-phenylethyl; and a halogenated hydrocarbon
group, such as 3,3,3-trifluoropropyl, 2-(perfluorobutyl)ethyl,
2-(perfluorooctyl)ethyl or p-chlorophenyl. In particular, methyl group,
phenyl group and alkyl groups containing 6 to 14 carbon atoms are
preferred as R.sup.1 in the invention.
In view of the consistency required for the silicone grease composition, it
is desirable that the suffix "a" in the foregoing formula be a number
ranging from 1.8 to 2.2, particualrly 1.9 to 2.1. Further, it is required
for the organopolysiloxanes used in the invention to have their viscosity
in the range of 50 to 500,000 cs at 25.degree. C. This is because the
grease composition shows a tendency to oil bleeding when it comprises the
organopolysiloxanes having viscosity lower than 50 cs at 25.degree. C.;
while, when it comprises organopolysiloxanes having viscosity higher than
500,000 cs at 25.degree. C., the grease composition has poor
spreadability. In particular, it is advantageous to use
organopolysiloxanes having their viscosity in the range of 100 to 10,000
cs at 25.degree. C. Additionally, the viscosity measurement in the
invention was made according to JIS K2283.
The proportion of organopolysiloxanes used as Component (B) in the present
grease composition is required to be from 5 to 15 weight %. In particular,
more desirable results are obtained when the proportion ranges from 7 to13
weight %. This is because when the organopolysiloxanes are used in a
proportion lower than 5 weight % the composition obtained becomes hard and
has poor spreadability; while when they are used in a proportion higher
than 15 weight % the composition obtained has insufficient thermal
conductivity.
The inorganic compound powder usable as Component (C) is a powder of at
least one inorganic compound having high thermal conductivity that is
selected from the group consisting of zinc oxide, alumina, boron nitride
and silicon carbide. The surface of such an inorganic powder may be
rendered hydrophobic by treatment with an organosilane, organosilazane,
organopolysiloxane or organic fluorine-containing compound, if desired.
The average particle size of the inorganic compound powder as Component (C)
is required to be in the range of 0.5 to 100 .mu.m, because the filling
rate of Component (C) in the present grease composition cannot be raised
as far as the inorganic compound powder has an average particle size
smaller than 0.5 .mu.m or greater than 100 .mu.m. Further, the inorganic
compound powder is required to be contained in the present grease
composition in a proportion of at most 30 weight %, because when the
proportion thereof is increased beyond 30 weight % the resulting
composition comes to have poor thermal conductivity. Further, it is
advantageous to the present grease composition that the proportion of
inorganic compound powder be from 0 to 25 weight %.
In preparing a silicone grease composition according to the invention, the
aforementioned Components (A) to (C) are mixed together by means of a
mixing machine, e.g., TRIMIX, TWINMIX or PLANETARY MIXER (trade names,
made by INOUE MFG., INC.), ULTRA MIXER (trade name, made by MIZUHO
INDUSTRIAL CO., LTD.) or HIVISDISPERMIX (trade name, made by TOKUSHU KIKA
KOGYO CO., LTD.). Therein, the mixing system may be heated to a
temperature of 50-150.degree. C., if needed. For rendering the thus
prepared mixture more homogeneous, it is desirable to perform a kneading
operation under high shear stress. Examples of a kneader usable for such
an operation include a three-rod roll kneader, a colloid mill and a sand
grinder. Of these kneaders, a three-rod roll kneader is used to advantage.
In accordance with embodiments of the invention, there is a big rise in the
thermal conductivity of silicone grease composition. Therefore, the
present silicone grease composition is well suited for use as thermal
conductive silicone grease for removing heat from exothermic electronic
parts.
Now, the invention will be illustrated in greater detail by reference to
the following Examples, but these examples should not be construed as
limiting the scope of the invention.
The entire disclosure of all applications, patents and publications, cited
above and below, and of corresponding Japanese application No. Hei
10-343037, filed, Dec. 2, 1998, is hereby incorporated by reference.
Additionally, the consistency measurement in each of Examples and
Comparative Examples is made according to the method defined in JIS
K-2220, and the thermal conductivity of each grease composition prepared
is measured at 25.degree. C. with a quick thermal conductivity meter,
QTM-500 (trade name, made by KYOTO ELECTRONICS MFG. CO., LTD.). The
particle size measurements are made with a Granulometer HR850 (trade name,
made by Cilas Alcatel Inc.). The viscosities of organopolysiloxanes used
in Examples are values measured at 25.degree. C.
Further, the criteria employed for evaluating the appearance and the
spreadability of each grease composition prepared are described below.
Appearance Evaluation
The surface condition of each grease composition is evaluated by visual
observation as follows;
.largecircle.:The grease composition surface is uniform and smooth.
.DELTA.:The grease composition surface is somewhat nonuniform.
X:The grease composition surface is nonuniform
Speadability Evaluation
Each grease composition in an amount of 0.2 g is put on an aluminum plate,
and spread with a finger. And the spreading condition of the grease
composition is evaluated as follows;
.largecircle.:The grease composition is spread smoothly.
.DELTA.:The grease composition is spread rather poorly and gives a rough
feeling.
X:The grease composition is spread poorly.
PREPARATION EXAMPLE 1
In a PLANETARY MIXER (trade name, made by INOUE MFG., INC.) having a volume
of 5 liter, 500 g of an aluminum nitride powder (A-1). having an average
particle size of 1.5 .mu.m and 500 g of an aliminum nitride powder (A-3)
having an average particle size of 8.0 .mu.m were thrown, and stirred for
30 minutes at room temperature to prepare a mixed aluminum nitride powder
(D-1). The average particle size of the mixed aluminum nitride powder
(D-1) was determined to be 3.4 .mu.m.
PREPARATION EXAMPLES 2 TO 12
Mixed aluminum nitride powders (D-2) to (D-12) were each prepared in the
same manner as in Preparation Example 1, except that aluminum nitride
powders having different average particle sizes were paired with each
other as shown in Table 1 and mixed in the weights (in grams) as set forth
in Table 1. The average particle sizes of the mixed aluminum powders (D-2)
to (D-12) thus prepared are also shown in Table 1.
TABLE 1
Aluminum Mixed aluminum nitride powder
nitride powder D-2 D-3 D-4 D-5 D-6 D-7 D-8 D-9 D-10 D-11
D-12
A-1 0 500 0 400 0 400 0 700 0 0
500
A-2 500 0 500 0 400 0 400 0 700 0
0
A-3 0 0 500 600 0 0 600 300 0 500
0
A-4 500 500 0 0 600 600 0 0 300 0
0
A-5 0 0 0 0 0 0 0 0 0 500
0
A-6 0 0 0 0 0 0 0 0 0 0
500
Average 4.4 3.9 3.6 3.8 4.6 4.1 3.7 2.7 3.6 2.9
4.6
particle
size (.mu.m)
after mixing
The symbols A-1 to A-6 used in Table 1 stand for the following;
A-1; Aluminum nitride powder (average particle size: 1.5 .mu.m, crystal
shape: amorphous)
A-2; Aluminum nitride powder (average particle size: 2.5 .mu.m, crystal
shape: amorphous)
A-3; Aluminum nitride powder (average particle size: 8.0 .mu.m, crystal
shape: amorphous)
A-4; Aluminum nitride powder (average particle size: 12.5 .mu.m, crystal
shape: amorphous)
A-5; Aluminum nitride powder (average particle size: 0.4 .mu.m, crystal
shape: amorphous)
A-6; Aluminum nitride powder (average particle size: 25 .mu.m, crystal
shape: amorphous)
EXAMPLES 1 TO 10 AND COMPARATIVE EXAMPLES 1 TO 8
Silicone grease composition samples according to the invention (Examples
1-10) and those for comparison (Comparative Examples 1 to 8) were each
prepared by weighing Components (A) to (C) in their respective amounts set
forth in Table 2 and Table 3 respectively, mixing those components for 30
minutes at room temperature by means of a PLANETARY MIXER (trade name,
made by INOUE MFG., INC.) having a volume of 5 liter, and then subjecting
the resulting mixture to a kneading operation with a three-rod roll
kneader three times. Each silicone grease thus prepared was examined for
characteristics (such as appearance, speadability, consistency and thermal
conductivity). The results obtained are shown in Tables 2 and 3.
Additionally, the symbols B-1, B-2, C-1 and C-2 used in Tables 2 and 3
represent the following ingredients:
B-1;
##STR1##
viscosity: 390 cs (25.degree. C.)
B-2;
##STR2##
viscosity: 500 cs (25.degree. C.)
C-1; Zinc oxide powder (average particle size: 2.0 .mu.m, amorphous)
C-2; Alumina powder (average particle size: 15 .mu.m, amorphous)
TABLE 2
Example
Component 1 2 3 4 5 6 7 8
9 10
Amount mixed (g)
Component (A)
D-1 700 0 0 0 0 0 0 0
0 0
D-2 0 700 0 0 0 0 0 0
0 0
D-3 0 0 700 0 0 0 0 0
0 0
D-4 0 0 0 700 0 0 0 0
0 0
D-5 0 0 0 0 700 0 0 0
0
D-6 0 0 0 0 0 700 0 0
0 0
D-7 0 0 0 0 0 0 800 0
0 0
D-8 0 0 0 0 0 0 0 800
0 0
D-9 0 0 0 0 0 0 0 0
870 0
D-10 0 0 0 0 0 0 0 0
0 870
Component (B)
B-1 100 100 100 100 0 0 100 100
0 130
B-2 0 0 0 0 120 120 0 0
130 0
Component (C)
C-1 200 200 200 200 0 0 0 0
0 0
C-2 0 0 0 0 80 80 100 100
0 0
Appearance .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
Spreadability .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
Consistency 310 305 295 303 330 325 295 300
345 338
Thermal Conductivity (W/mk) 2.9 2.8 2.8 2.9 2.7 2.7 2.9 2.8
3.0 3.0
TABLE 3
Comparative Example
Component 1 2 3 4 5 6 7 8
Amount
mixed (g)
Component
(A)
A-1 700 0 0 0 0 0 0 0
A-2 0 700 0 0 0 0 0 0
A-3 0 0 700 0 0 0 0 0
A-4 0 0 0 700 0 0 0 0
A-5 0 0 0 0 700 0 0 0
A-6 0 0 0 0 0 700 0 0
D-11 0 0 0 0 0 0 700 0
D-12 0 0 0 0 0 0 0 700
Component
(B)
B-1 100 100 100 100 100 100 100 100
B-2 0 0 0 0 0 0 0 0
Component
(C)
C-1 200 200 200 200 200 200 200 200
C-2 0 0 0 0 0 0 0 0
Appearance X X X X no- X .DELTA. .DELTA.
Spread- X X X X grease X .DELTA. .DELTA.
ability
Consistency 220 227 230 235 -- 255 270 265
Thermal 2.5 26 2.5 2.6 -- 2.5 2.6 2.5
Conductivity
(W/mk)
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